Lab 9: Reflection and Refraction

– Law of Reflection– Law of Refraction (Snell’s Law)

1. Index of Refraction2. The Critical Angle3. Total Internal Reflection4. Dispersion5. Light Passing through a Window Pane or Prism6. How Large does a Mirror Need to be?7. Location of Mirror Image8. Rainbows9. Corner Reflectors10. Fiber Optics11. Polarization by Reflection

• Light ray– Originates at a point source– Travels straight– Changes direction at interface

• Reflection & refraction in this lab

• Object– Point source of light rays

• Image– Apparent convergence point of light rays from object

• Draw diagrams involving– Light rays– Interface– Angles

• Estimate angles to the tenth of a degree– Take several measurements and then average them

Light Rays

• indicated as arrows• from object extend outward

Light Rays

light unit:a ray of light made by a slit

white light

Interface

Cross-sectional View

medium

airinterface :boundary between different media

normal :direction perpendicular to interface

Reflection (Specular)

Cross-sectional View

mirror

air

air

iangle of incidence (i )r angle of reflection (r )

angles measured from normal

Top view

Aim light ray at the center of semicircle.

A

ray of light

M

Experiment #1

A

M

ray of light

Experiment #2

Component Line

A

(degree)M

(degree)sinA sinM sinA/sinM (= nglass)

0 N/A

10

85

Use the “degree” mode on your calculator

i

(degree)r

(degree)r – i

(degree)

0

10

85

Reflection

Refraction #1